173 - Tetralogy of Fallot in Premature Neonates: Risks and Outcomes

Poster Number: 173
Publication Number: 173.101

Chinenyenwa Mpamaugo, University of Washington School of Medicine, Seattle, WA, United States; Aarti H. Bhat, Seattle Children's, Seattle, WA, United States; Josiah M. Penalver, Seattle Children’s Hospital, Tacoma, WA, United States; Eyal Sagiv, Seattle Children's, Seattle, WA, United States; sathish mallenahalli chikkabyrappa, Seattle Children's, sattle, WA, United States

Background: In the United States, the leading cause of neonatal morbidity and prenatal mortality are preterm birth and congenital malformations. Congenital heart defects are the most common type of birth defects of which tetralogy of Fallot is the most prevalent cyanotic congenital heart disease. Studies have shown that premature infants with tetralogy of Fallot (pTOF) have up to 13-fold increase in mortality, but the evolution and outcome of multi-level right ventricular outflow tract obstruction (RVOT) in pTOF remains unclear.

Objective: We evaluated both clinical and imaging features of pTOF and correlated this with mortality and type of intervention [valve-sparing (VS) vs transannular patch (TAP)].

Design/Methods:
A retrospective review was completed of pTOF born at gestational age < 37 weeks between Jan 2010 and Dec 2020 and admitted to our tertiary hospital as identified from institutional databases. Infants with pulmonary atresia or nonconfluent pulmonary arteries were excluded. Demographic, echocardiographic, catheterization and surgical data were compiled and reviewed.

Results:
24 pTOF met inclusion criteria ranging from 24 - 36 6/7 weeks gestation and birthweight (BW) ranging from 0.35 – 2.8 kg. Additional extracardiac concerns were present in 62% of patients. Interventions were performed at an average of 3.3 months. Cyanotic spells were observed in 10 pTOF, all were started on β-blocker therapy and all had significant increase in RVOT obstruction leading to repair at a mean postnatal age of 3.5 months, including 1 who underwent emergent catheterization. TAP was needed in 60% of this group. 14 pTOF did not have any documented cyanotic spells and TAP was need in 54% of those patients. In pTOF with BW < 1.5 kg, only 5/9 survived to complete repair and only 1 was VS. Mortality was 17% (n = 4); all of which were pTOF with BW < 1 kg (average 585 g), had intra-uterine growth restriction (IUGR), were delivered by urgent C-Section and died before surgical intervention, although 1 received an RVOT stent. Of the surviving cohort, 20% suffered adverse events (2 pericardial effusion, 1 pleural effusion, 1 esophageal injury).
Conclusion(s):
In our cohort, no IUGR pTOF with BW  < 1kg survived to surgery, thus emphasizing the significance of birth weight and mortality in pTOF.  Despite the rapid increase in dynamic RVOT obstruction in pTOF with cyanotic spells, their age at repair and feasibility for VS surgery was equivalent to the group that did not have any reported cyanotic spells. pTOF without cyanotic spells were equally likely to need TAP even though they had no dramatic increase in RVOT obstruction.

Chinenyenwa Mpamaugo CV Residency1.pdf